Coated abrasive articles generally have an abrasive layer, comprising abrasive particles and one or more binders, secured to a major surface of a backing. In many cases, an additional coating called a supersize, typically including a grinding aid, is included over the abrasive layer. The backing and/or abrasive layer may include more than one layer. For example, the backing may be a laminate backing, optionally having one or more backing treatments thereon.
In some coated abrasives, the abrasive layer may include a make layer and abrasive particles embedded in the make layer and covered by a size layer which helps retain the abrasive particles.
In other coated abrasives, abrasive particles are dispersed more or less evenly throughout a polymeric binder. For example, this is commonly the case when the abrasive layer is formed of shaped abrasive composites, typically having a predetermined shape (e.g., a precise shape) and arrangement on the backing. Such abrasives are typically prepared by coating a slurry of a corresponding binder precursor and abrasive particles on a tool having shaped cavities, laminating a backing to the tool, curing the binder precursor to form shaped abrasive composites secured to the backing, and then removing the tool.
It is known in the abrasive arts to use infrared lasers such as, for example, carbon dioxide (i.e., CO2) lasers operating at a wavelength of 10.6 micrometers to convert coated abrasive roll goods into sheets and/or discs suitable for sale to consumers. However, using this converting method (i.e., perforating and/or cutting by infrared laser-induced ablation) with adhesive-backed coated abrasives can lead to edge contamination by the adhesive resulting in difficulty in peeling off the associated release liner. Additionally, pieces of adhesive may become lodged at the interface between the abrasive layer and the workpiece, potentially creating scratches.
The CO2 laser produces a beam of long wave infrared (LWIR) light with the principal wavelength centered between 9.2 and 12 micrometers and tunable within this range. Average output power of CO2 lasers is typically highest at 10.6 micrometers and declines when tuned to other wavelengths. Accordingly, the vast majority of commercial CO2 laser processing is done at a single wavelength, 10.6 micrometers.
In some cases, infrared laser converting can result in hardened, raised, and/or sharp edges being formed in the abrasive layer adjacent to cuts and perforations made by the laser. These hardened edges can also adversely affect the performance of the coated abrasive.
In the case of coated abrasive that include a powdery supersize (e.g., a zinc stearate supersize), infrared laser ablating can result in the abrasive particles becoming covered with melted supersize thereby reducing anti-loading performance of the supersize and potentially inducing scratches on the abraded surface.